GE UR Series L90, Instruction Manual

Page: 445 / 846

GE Multilin L90 Line Current Differential System 5-307
5 SETTINGS 5.7 CONTROL ELEMENTS
5
The POTT1 pilot scheme operates the same way as the regular POTT scheme, except hard-coded connections to phase
and ground distance elements are removed to allow the user to choose directional elements, for example ground OC direc-
tional elements. This allows a user to apply the POTT1 scheme using solely directional elements to achieve better coordi-
nation, rather than mixing up distance and ground OC directional elements together.
The settings and application guidance for the POTT scheme applies to the POTT1 scheme. See the POTT section.
• DIR FWD1..3 : This setting defines the FlexLogic operand of a protection element used for keying the communication
channel and initiating operation of the scheme. Good directional integrity is the key requirement for an over-reaching
forward-looking protection element used as DIR FWD.
Even though any FlexLogic operand can be used as DIR FWD allowing the user to combine responses of various pro-
tection elements, or to apply extra security conditions through FlexLogic equations, this signal is primarily meant to be
the output operand from either the Negative-Sequence Directional IOC or Neutral Directional IOC. Both of these ele-
ments have separate forward (FWD) and reverse (REV) output operands. The forward indication is used (NEG SEQ
DIR OC1 FWD or NEUTRAL DIR OC1 FWD).
Figure 5–164: POTT1 (GROUND) SCHEME LOGIC
SETTING
SETTING
FLEXLOGIC OPERAND
FLEXLOGIC OPERAND
SETTING
SETTING
POTT1 SCHEME
FUNCTION:
Enabled
Custom
DIR FWD1:
LINE PICKUP LEO PKP
Off
POTT1 OP
POTT1 PERMISSIVE ECHO:
POTT ECHO COND:
Disabled = 0
Off = 0
Disabled
837039A2.CDR
Off = 0
SETTINGS
SETTINGS
SETTINGS
SETTINGS
SETTINGS
POTT1 RX PICKUP
DELAY:
TRANS BLOCK PICKUP
DELAY:
LINE END OPEN PICKUP
DELAY: ECHO DURATION:
TRANS BLOCK RESET
DELAY:
POTT1 SEAL-IN
DELAY:
AND
AND
AND
AND
AND
OR
0
t
RST
0
t
RST
t
PKP
t
PKP
t
PKP
0
ECHO LOCKOUT:
Echo duration and lockout logic
SETTINGS
POTT1 RX1:
POTT1 RX2:
POTT1 RX3:
POTT1 RX4:
POTT1 NO OF COMM
BITS:
Off = 0
Off = 0
Off = 0
Off = 0
OR
FLEXLOGIC OPERANDS
POTT NO OF COMM
BITS:
POTT1 TX1
POTT1 TX2
POTT1 TX3
POTT1 TX4
ECHO TABLE
TRANSMIT TABLE
Phase
Selector
RX
RX
RUN
RUN
FLEXLOGIC OPERANDS
POTT NO OF COMM
BITS:
POTT1 TRIP A
POTT1 TRIP B
POTT1 TRIP C
POTT1 TRIP 3P
TRIP TABLE
Phase
Selector
RUN
AND
0
100 msec
SETTING
POTT1 SCHEME BLOCK:
OFF = 0
AND
FLEXLOGIC OPERANDS
AR FORCE 3P TRIP
OPEN POLE OP
FLEXLOGIC OPERANDS
AR FORCE 3P TRIP
OPEN POLE OP
Phase
Selector
FLEXLOGIC OPERANDS
AR FORCE 3P TRIP
OPEN POLE OP
DIR FWD2:
Off = 0
DIR FWD3:
Off = 0